Zip Code Regex Tester
Validate postal codes with regular expressions
^\d{5}(-\d{4})?$Regex Flags
No matches found
Pattern Explanation
^\d{5}(-\d{4})?$No explanation available
About Zip Code Regex Patterns
Postal code formats vary by country: US uses 5 digits (with optional +4), UK uses alphanumeric patterns like SW1A 1AA, Canada uses alternating letters and digits like K1A 0B1. Each requires different regex patterns.
Our zip code regex tester provides patterns for common formats and helps you build validation for your target countries.
Why Validate Zip Codes?
Address validation is critical for delivery services, location-based features, and tax calculation. Invalid postal codes cause failed deliveries, missed customers, and incorrect location data.
Format validation catches typos early. A UK postcode field that accepts "90210" is clearly broken—appropriate regex prevents cross-format errors.
Building the Pattern
Country-specific patterns:
US (ZIP): ^\d{5}$ (basic) or ^\d{5}(-\d{4})?$ (with optional +4) UK: ^[A-Z]{1,2}\d[A-Z\d]? ?\d[A-Z]{2}$ (complex alphanumeric) Canada: ^[A-Z]\d[A-Z] ?\d[A-Z]\d$ (alternating letter-digit)
For international forms, either detect country first or use lenient validation.
Common Use Cases
- Shipping address forms
- Store locator features
- Tax jurisdiction detection
- Address autocomplete validation
Pro Tip
For US addresses, validate ZIP codes against the USPS database for existence, not just format. Many correctly-formatted codes don't exist.
Other Regex Patterns
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